Significance

Syntactic distance is standardly measured hierarchically only by counting the nodes in a tree-like structure. The dominance of hierarchy over the other logically possible measure of distance—e.g., counting words in a linear order—stems from a large body of research. We show a strong preference for the linear strategy in coordination structures in South Slavic languages, with a design comparing agreement controllers that can come either before or after their target. A large-scale study over six geographically and linguistically distinct varieties discovered remarkable uniformity in this preference. Variation discovered was mostly intraindividual, strongly suggesting that a language can entertain synchronous “multiple grammars,” the most striking of which is the one requiring direct reference to linear order.

Abstract

Hierarchical structure has been cherished as a grammatical universal. We use experimental methods to show where linear order is also a relevant syntactic relation. An identical methodology and design were used across six research sites on South Slavic languages. Experimental results show that in certain configurations, grammatical production can in fact favor linear order over hierarchical structure. However, these findings are limited to coordinate structures and distinct from the kind of production errors found with comparable configurations such as “attraction” errors. The results demonstrate that agreement morphology may be computed in a series of steps, one of which is partly independent from syntactic hierarchy.